1. Field of the Invention
This invention relates generally to systems for detecting and calculating the coordinates of a projectile in a target zone, and in particular to an apparatus for evaluating the position and speed of a ball.
2. Description of the Prior Art
The main aim of a baseball pitcher is to throw the ball at a high speed across the plate within the strike zone but in areas where hits occur less frequently. As a strategy, the pitcher attempts to avoid hits by changing frequently the velocity, and the position of the ball as it penetrates the strike zone. There is a need, therefore, for a training apparatus that can be used by a baseball pitcher to improve his performance in pitch delivery and placement. Radar guns have been used to measure the velocity of a pitched baseball but its use has had only minimal impact on the training of baseball pitchers since it cannot evaluate the accuracy of the throw.
U.S. Pat. No. 4,563,005 discloses an apparatus for detecting and computing the location of a pitched baseball. However, this apparatus needs a sophisticated program to identify the position of the ball upon reception or non-reception on sequentially activated emitters. Also, a large number of emitters and detectors are required to evaluate the balls position with proper accuracy.
Furthermore, no provision is made to avoid interference of external light with the signal transmitted by the emitters.